Carbohydrates and Diabetes Flashcards
Define Monosaccharide, giving 3 examples and where they are found.
Simple sugar.
Glucose - fruit, veg, honey
Fructose - fruits, manufactured food
Galatactose - digestion of lactose
Define Disaccharide, giving 3 Examples and where they are found.
2 simple sugars linked by glycosidic bond between anomeric hydroxyl of cyclic sugar and hydroxyl of second sugar.
Maltose - malt wheat, barley, beer
Sucrose - most common - table sugar, sugar cane, sweet root veg
Lactose - milk
Define Oligosaccharide.
Chain of 3+ monosaccharides linked by glycosidic bonds
Define Polysaccharide and state the predominant mono. and provide other examples
Multiple sugars linked by glycosidic bonds.
D-Glucose
starch, glycogen and cellulose
Starch is a Polysaccharide. State where it is Found and the Two Types of Starch.
Plant cells
unbranched = amylose α-1,6-D
branches = amylopectin α-1-4-D
Glycogen is a Polysaccharide. State where it is Found and Explain the Features of its Structure.
found as a stored carbohydrate in animals
Highly Branched
- surface area for breakdown
Compact from polymer chain coiling
- allows large amount of energy storage
Glycosidic bonds between single chains = a-1,4 link
Where are Carbohydrates Generally Found?
in breads, milk, bean, corn
How are Carbohydrates Formed? (think organically)
Photosynthesis
Provide the 2 Types of Photosynthesis.
Light Dependent
light energy+water ➵ oxygen+ATP+NADPH
Light Independent - Calvin cyle
CO2+ATP+NADPH➵glucose+ADP+Pi+H20+NAP
What are the Functions of Carbs? (5)
- energy storage
- energy production
- build macromolecules - DNA, ATP
- assist in lipid metabolism
- biosynthesis of amino acids
How is Starch Released, and in which pH?
By serous acini in pH 6.7
Give 3 Enzymes used to break down the Main 3 Disaccharides.
Maltase
Sucrase
Lactase
How is more Glucose made, if not from Food?
gluconeogenesis
- glycerol is broken down into glucose
What are the Daily Requirements for Carbs?
2-5 = 15grams
5-11 = 20grams
11-16= 25grams
16-18 = 30grams
Why Can’t Cellulose be Digested?
enzymes can’t hydrolyse the β-1 bonds
3 Places Where Carbohydrates are Digested.
in the oral cavity
in the stomach
in the gastro-intestinal tract of the small intestine
Explain the Two Types of Digestion in the Oral Cavity and the end result?
Mechanical - by parotid and submandibular gland
Chemical - enzymatic
- salivary α-amylase
end result = broken down into monosaccharides
Explain How Salivary α-Amylase is Secreted in the Oral Cavity, the pH it Works at and the Function.
- by serous acini of parotid and submandibular gland
- optimum pH = 6.7
- it hydrolyses α-1,4-linkage from oligo into poly
- works for 1-2 hrs in the stomach before deactivation by gastric acids
State the 2 Enzymes found in the GIT.
- pancreatic amylase
- brush border enzymes
What is Pancreatic Amylase Secreted by? Where is it Secreted? What is the Optimum pH and Function?
- secreted by pancreatic exocrine acini into duodenum through pancreatic duct
- pH = 6.7-7
- hydrolyse α-1,4-linkage and digests more complex carbohydrates
What is the Function of Microvilli in the Small Intestine?
to increase SA, facilitating absorption
How is Galactose and Glucose Absorbed? (4)
for jokes rememberance: The G is SOOO big how can it get through, there
- from intestinal lumen, enters epithelial cell via apical border
- uses active transport and sodium dependent co-transporters (SGLT1)
- leaves epithelial cell via basolateral side
- facilitated diffusion and glucose-cotransporter 2 (GLUT2)
= into blood circulation
How is Fructose Absorbed?
For jokes: F looks like a 5
- from intestinal lumen, enters epithelial cell with GLUT-5
- binds and changes shape
- Leave cell - facilitated diffusion and GLUT-2
= into blood circulation
What Problems are there With Monosaccharides being Absorbed?
the shape makes them polar
= unable to cross the liquid bilayer
solution - need transporter enzymes
